Thermoplastic materials have been used for some time in packaging food articles. The central processing of food items, and the packaging of food items to permit relatively easy preparation by for example the use of microwave ovens, is increasingly common. With the increasing popularity of such methods of food preparation, the demands on packaging materials for such food items have also increased.
Such materials must possess good toughness combines with resistance to elevated temperatures during a heating cycle. Additionally, such materials should exhibit high oxygen barrier characteristics to protect the typically oxygen sensitive food item.
Of interest is U.S. Pat. No. 4,188,443 issued to Mueller which discusses a multilayer film of three or five layers in which one or both of the outside layers comprises a polyester.
Of interest is U.S. Pat. No. 4,576,988 issued to Tanaka et al disclosing a melt molding material having a silicon-containing ethylene vinyl alcohol copolymer coated with vinylidene chloride.
Of interest is UK Patent Application No. GB2121062A (Mollison) which discusses a pouch for flowable materials made from a film comprising a laminate of a base film and a sealant film. The base film may be polyethylene terephthalate film, or saponified ethylene vinyl acetate film. A layer of polyvinylidene chloride may be interposed between the base film and sealant film.
Of interest is Proceedings of the Fifth Annual International Coextrusion Conference and Exhibition, Oct. 9-11, 1985 discussing the blending of ethylene vinyl alcohol copolymer with for example polyethylene terephthalate.
It is an object of the present invention to provide a packaging material with heat resistant properties.
It is an additional object of the present invention to provide such a packaging film with good dimensional stability.
It is still another object of the present invention to provide a packaging material suitable for use in microwavable package systems.
It is yet another object of the present invention to provide a packaging material useful in microwavable applications, and with high oxygen barrier properties.